An automatic sewing machine of the type as defined is known from a catalogue of the Necchi company, "IMB 1985", under the designation, Necchi UAN 2531/A. With this known automatic sewing machine the workpieces to be sewn are drawn linearly by means of a workpiece holder of the feeding device out of a transfer position, which is associated with a preparatory station in the form of a folding device, via a carrier plate of the automatic sewing machine into a sewing position in which sewing takes place. During this sewing operation new workpieces can be prepared in the preparatory station and positioned relative to one another and relative to the sewing head situated at a distance. After sewing the finish-sewn workpieces are removed from the automatic sewing machine, the workpiece holder is moved back to he transfer position by appropriate triggering of the feeding device, and new workpieces are brought into the sewing position where a new sewing cycle commences. During this last described cycle time sewing cannot take place because no workpieces are in the sewing position.
It is further known from U.S. Pat. No. 3,878,801 to arrange ahead of a sewing head two preparatory stations having two feeding devices situated on both sides of the sewing head. With this arrangement a higher cycle time and shorter idle times of the sewing head are possible; however, two extremely costly preparatory stations are necessary.
Further, it is known from U.S. Pat. No. 3,528,378 to provide parallel to the principal longitudinal direction of a sewing head a preparatory station in the form of a folding device by which prepared workpieces are moved along a U-shaped path into a sewing position by means of a carriage.
Finally, a feeding device is known from U.S. Pat. No. 3,143,091 which has two material grippers which can be transferred from a receiving station to a sewing station on rails parallel to one another. The material grippers convey folded pocket pieces, the material grippers themselves having parts of the folding devices and moving these also. The material grippers are moved together with the folded pocket pieces always in a state lifted clear from the working plate, i.e. they are not displaced over the working plate. This is essential because at least the path of one material gripper, which is preset depending on the design, surrounds the path of the other material gripper on the outside and above. The paths of the two material grippers therefore extend like two turned over one another and inverted Us. It already follows from the preceding features and characteristics that the folded pocket pieces are only conveyed without the main part of the workpiece to which they are to be sewn, that is for example a trouser piece.